U.S. patent number 3,824,527 [Application Number 05/277,839] was granted by the patent office on 1974-07-16 for wire-in-slot electrical connections.
This patent grant is currently assigned to AMP Incorporated. Invention is credited to William Robert Evans.
United States Patent |
3,824,527 |
Evans |
July 16, 1974 |
WIRE-IN-SLOT ELECTRICAL CONNECTIONS
Abstract
Electrical connecting device comprises a generally V-shaped
member having wire receiving slots extending into corresponding
side edges which are adjacent to the bight of the V. The plate
sections of the V are preferably kinked in alignment with the
slots. Upon insertion of a wire, the plate sections are resiliently
stressed by the wire in a manner to cause them to move towards each
other. Additionally, the individual plate sections may be flexed by
stressing of the kinked sections in the manner of a cylindrical
spring.
Inventors: |
Evans; William Robert
(Hummelstown, PA) |
Assignee: |
AMP Incorporated (Harrisburg,
PA)
|
Family
ID: |
23062576 |
Appl.
No.: |
05/277,839 |
Filed: |
August 3, 1972 |
Current U.S.
Class: |
439/400 |
Current CPC
Class: |
H01R
43/015 (20130101); H01R 4/2458 (20130101) |
Current International
Class: |
H01R
4/24 (20060101); H01R 43/01 (20060101); H01r
013/38 () |
Field of
Search: |
;339/95,97-99 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Moore; Richard E.
Claims
What is claimed is:
1. An electrical connecting means for forming an electrical
connection with an insulated wire comprising:
a generally V-shaped stamped and formed member having a pair of
divergent plate sections connected by a bight,
a wire receiving slot in each of said plate sections, said wire
receiving slots extending into corresponding first edges of said
plate sections which edges are adjacent to said bight, said slots
extending substantially parallel to said bight and being
substantially equidistant from said bight,
said slots having sides which extend substantially normally of
their respective plate sections so that the center-lines of said
slots intersect,
each of said plate sections having a generally semi-cylindrical
kink therein in alignment with its respective slot, said kinks
extending from the inner ends of said slots to the edges of said
plate sections which are opposite to said first edges, the
amplitude of said kinks determining the width of said slots
whereby
upon movement of said wire laterally of its axis and into said
slots, said sides of said slots penetrate said wire to form an
electrical and mechanical connection therewith, and said wire
imposes forces on said sides of said slots which tend to flex said
plate sections angularly towards each other thereby to provide
continuing contact force between said connecting device and said
wire.
2. A connecting means as set forth in claim 1 wherein said first
edge of each of said plate sections is inclined divergently on each
side of each slot thereby to guide said wire into said slots.
3. A connecting means as set forth in claim 1 and an additional
connecting means, said additional connecting means being
substantially similar to, and beside, said connecting means, said
additional connecting means being connected to said connecting
means by means of a connecting bight, said connecting bight
extending between adjacent plate-like sections of said connecting
means and said additional connecting means, whereby said connecting
means and said additional connecting means are substantially
W-shaped, said connecting means and said additional connecting
means being adapted to connect two wires extending axially towards
each other.
4. A connecting means as set forth in claim 1, said connecting
means having mounting post means integral therewith and extending
from said bight portion on the side thereof which is opposite to
said one side, said device being mounted on a printed circuit board
with said mounting post means extending through an opening in said
board and in electrical contact with conductor means on said
board.
5. A connecting means as set forth in claim 1 and a plurality of
additional connecting means, said connecting means and said
additional connecting means being mounted on an insulating support
member, said connecting means and said additional connecting means
being arranged in a row with all of said connecting means being in
the same orientation and with each connecting means nested within
adjacent connecting means.
6. A connecting means and a plurality of additional connecting
means as set forth in claim 5, said insulating support member
comprising a printed circuit board, each connecting means having a
post portion extending from its bight, said post portions being
electrically connected to conductors on said printed circuit
board.
7. A connecting means and a plurality of additional connecting
means as set forth in claim 5, said insulating support member
comprising a multi-contact connector block, each of said connecting
means having contact means integral therewith for forming
disengageable connections with further conductors.
8. A connecting means as set forth in claim 1 and an additional
connecting means, said connecting means and said additional
connecting means being in opposed offset relationship and one plate
section of said connecting means being integral with one plate
section of said additional connecting means.
9. An electrical connection of a single conductor to a connecting
means:
said connecting means comprising a generally V-shaped stamped and
formed member having a pair of divergent flat plate sections
connected by a bight,
a conductor-receiving slot in each of said plate sections, said
slots extending into corresponding first edges of said plate
sections which edges are adjacent to said bight, said slots
extending substantially parallel to said bight,
said conductor extending obliquely of said plate sections and being
disposed in each of said slots.
10. An electrical connection as set forth in claim 9, said
connecting member being resiliently stressed in a manner tending to
flex said plate sections towards each other.
11. An electrical connection as set forth in claim 9, each of said
connecting means having a generally semi-cylindrical kink in
alignment with its respective slot, said kinks extending from the
inner ends of said slots to the edges of said plate sections which
are opposite to said first edges, said kinks functioning as
resiliently stressed semi-cylindrical springs and maintaining
contact pressure between edge portions of said slots and said
conductor.
12. A connecting means for forming an electrical and mechanical
connection with a conductor comprising:
a flat plate-like member having a wire-receiving slot extending
into one of its edges, said slot having an inner end which is
spaced from the edge which is on the opposite side of said member
from said one edge,
a generally semi-cylindrical kink in said member extending from
said inner end of said slot to said opposite edge whereby
upon movement of said conductor laterally of its axis into said
slot, the edges of said slot are forced relatively apart with
concomitant resilient deformation of said kink, and said edges of
said slot are maintained in continuing contact with said wire by
virtue of the resilient deformation of said kink.
13. A connecting device as set forth in claim 12, said connecting
device having an additional plate-like member which is
substantially similar to said plate-like member, said additional
plate-like member defining a plane which intersects said plate-like
member and being connected to said plate-like member by a bight,
said plate-like member and said additional plate-like member
forming a V-shaped connecting means.
14. An electrical connection between a conductor and a sheet metal
connecting means,
said sheet metal connecting means comprising a flat plate-like
member having a slot extending into one of its edges, said slot
having an inner end which is spaced from the edge which is on the
opposite side of said plate-like member from said one edge,
a generally semi-cylindrical kink in said member extending from
said inner end of said slot to said opposite edge,
said conductor being in said slot and being resiliently gripped by
the edges of said slot, said kink being resiliently deformed and
functioning as a spring means serving to maintain said edges of
said slot in engagement with said conductor.
15. A method of making a slotted plate-type connecting means having
a slot of a width W which is less than the thickness of the
conductor for which said connecting means is intended, said method
comprising the steps of:
punching a slot having a width W' in a flat metal plate where W' is
greater than W,
forming a generally semi-cylindrical kink in said plate in
alignment with said slot and extending across said plate from the
inner end of said slot, and
in forming said kink, moving the edges of said slot towards each
other until said slot is of a width W, said kink in the finished
connecting means functioning as a spring which joins two sides of
said connecting means and which permits said edges of said slot to
move apart upon movement of a conductor into said slot.
Description
BACKGROUND OF THE INVENTION
This invention relates to electrical connections of the type in
which a conductor is forced into a slot having a width such that
the edges of the slot penetrate the insulation of the conductor and
establish contact therewith.
Slotted plate-type electrical connections have been widely used for
several years and are being used to an increasing extent under a
variety of circumstances. The simpliest form of slotted plate-type
connecting device comprises a flat metal plate having a slot formed
therein which is adapted to receive the wire. When the wire is
forced into the slot, the portions of the plate member on each side
of the slot are stressed in the manner of a rigid cantilever beam
and by virtue of their stressed condition, electrical contact is
maintained with the wire. In these types of slotted plate-type
connecting devices, contact depends upon an extremely rigid spring
system since the cantilever beams of the system are extremely stiff
and capable of undergoing only limited elastic deflection.
The instant invention is specifically directed to the achievement
of a slotted plate-type connecting device having improved spring
systems for maintaining the electrical contact with the wire which
permit the use of relatively thinner metal stock in the connecting
device than has heretofore been practical. In general, the
invention is directed to the achievement of a connecting device
which is efficient in the sense that it has spring systems for
establishing electrical contact which utilize the properties of the
material from which the contact is made to a high degree. The
invention is further directed to the achievement of a connecting
device which is inherently rigid and strong and which can be
manufactured at a low cost to a high degree of precision. As will
be demonstrated below, the principles of the invention can be used
in a wide variety of connectors and under a wide variety of
conditions.
It is accordingly an object of the invention to provide an improved
slotted plate-type electrical connecting device. A further object
is to provide a slotted plate-type connecting device having
improved spring characteristics. A still further object is to
provide a connecting device which can be manufactured from a wide
variety of materials and from materials of differing thicknesses. A
further object is to provide an improved method of providing the
wire receiving slot in a slotted plate-type connecting device.
These and other objects of the invention are achieved in a
preferred embodiment thereof which is briefly described in the
foregoing abstract, which is described in detail below, and which
is shown in the accompanying drawings in which:
FIG. 1 is a perspective view of one form of connecting device in
accordance with the invention which is adapted to be mounted in a
printed circuit board, this view showing the connecting device
exploded from the printed circuit board and showing the lower
portion of an insertion tool for inserting a wire into the
connecting device.
FIG. 2 is a perspective view which is similar to FIG. 1 showing a
wire inserted into the slots of the connecting device.
FIG. 3 is a plan view of the stamped blank from which the
connecting device of FIG. 1 is formed.
FIG. 4 is a plan view of the blank after it has been kinked in
order to size the wire receiving slots.
FIG. 5 is a top plan view of the connecting device of FIG. 1 in its
normal condition and prior to insertion of the wire.
FIG. 6 is a view similar to FIG. 5 but showing the connecting
device after insertion of the wire and illustrating one mode of
stressing the connecting device.
FIG. 7 is a fragmentary view of one of the plate sections of the
connecting device of FIG. 1 in its normal condition.
FIG. 8 is a view similar to FIG. 7 but showing the plate section
after insertion of the wire, this view illustrating another mode of
stressing the connecting device by the wire.
FIG. 9 is a top view of an embodiment of the invention adapted for
connecting a tap-wire to a through-wire splice.
FIG. 10 is a perspective exploded view of a connector for forming
butt-splice connections between three pairs of wires, this view
showing the metallic connecting device exploded from the connector
housing.
FIG. 11 is a view of the connector of FIG. 10 showing the parts in
assembled relationship.
FIG. 12 is a perspective view of an electrical contact pin having a
connecting device in accordance with the invention integral
therewith.
FIG. 13 is a view showing an alternative form of contact pin
provided with a connecting device in accordance with the
invention.
FIG. 14 is a fragmentary perspective view of a multicontact
electrical connector containing contact pins of the type shown in
FIG. 12, this connector being adapted to connect the conductors of
a ribbon-cable to conductors on a printed circuit board.
FIG. 15 is a fragmentary perspective view of a printed circuit
board having connecting means in accordance with the invention
mounted thereon.
An electrical connecting means 2 in accordance with the invention
comprises a generally V-shaped member of conductive sheet metal
having divergent plate-sections 4, 6 which are integral with each
other at a bight 8. The connecting means of FIG. 1 has an integral
mounting post 10 extending from the bight which is adapted to be
inserted through a hole 11 in a printed circuit board 13 and
soldered to a conductor on the underside of the board. Wire
receiving slots 12, 14 in the plate sections 4, 6 extend inwardly
and parallel to the bight 8 from the upper side, as viewed in FIG.
1, of the connecting member, the edges 16, 18 of this side sloping
towards the slots in order to guide the wire into the slots during
insertion. Each plate section has a generally semi-cylindrical kink
20 which extends from the inner end 15 of its slot to the lower
side of the connecting member. As will be explained below, these
kinks serve as resilient springs when the wire is inserted into the
slots and contribute to the contact force at the electrical
interface of the wire in the connecting means. As will also be
explained below, these kinks permit the manufacture of connecting
members with extremely narrow slots for the reception of fine gauge
wires.
Advantageously, one of the slots, 12, 14 has a width which is
substantially less than the diameter of the conducting core 22 of
the wire and the other slot has a width which is substantially
equal to or greater than the diameter of the core of this wire so
that a good electrical contact is obtained at the narrow slot and a
mechanical strain relief for the wire is provided by the wider
slot.
One form of insertion tool 26 for inserting the wire into the slots
has a shank 28 and a central triangular wire pusher 30 which is
adapted to move between the opposed faces of the plate sections 4,
6. Additionally, legs 32 depend from the shank on each side of the
wire pusher 30 and are spaced from the wire pusher by a distance
such that they will engage the wire outwardly of the plate sections
so that the tool can move downwardly past the upper end of the
connecting device. To insert the wire, it is aligned with the slots
12, 14 and the tool is moved downwardly until the wire has moved
into the slots, preferably to the inner ends 15 thereof. As shown
best in FIG. 2, the wire will be displaced downwardly between the
opposed faces of the plate sections 4, 6 and the insulation of the
wire will be penetrated as shown in FIGS. 5 and 6.
Connecting devices in accordance with the invention can be
manufactured of any suitable conductive sheet metal such as brass
or phosphor bronze. The specific device shown in FIG. 1 is
manufactured by simply stamping the blank 2', FIG. 3, with the
slots 12', 14' of the blank being substantially wider than the
slots in the finished connecting member. The blank is then kinked
by forming cylindrical depressions therein in alignment with the
slots as shown at 20 in FIG. 4. This kinking operation has the
effect of moving the sides of the slots relatively towards each
other and is carefully controlled to produce the desired widths in
the slots.
This method of manufacture is distinctly advantageous for the
reason that there is for any given stock metal, a lower limit to
the width of an opening that can be punched in the stock. As a
general rule of thumb, it can be assumed that it is impractical to
punch an opening in sheet metal which has a width that is less than
the thickness of the sheet metal; if smaller openings are punched,
excessive tool wear and tool breakage result to an extent that an
operation becomes impractical. Slotted plate-type connecting
devices frequently must be provided with extremely narrow slots for
fine wires; for example, an AWG 32 wire has a diameter of about
0.008 inch and would therefore require a slot having a width of
about 0.006 inch or less for effective electrical contact. Under
many circumstances, the use of stock metal having a thickness of
less than 0.006 inch is totally impractical and conventional
punching techniques would not permit the punching of a 0.006 inch
wide slot in stock metal having a thickness greater than 0.006
inch. A kinking procedure of the instant invention permits the
achievement of these narrow slots regardless of the thickness of
the stock metal.
Referring now to FIGS. 5 and 6, the V-shaped connecting device of
FIG. 1 may be stressed upon insertion of the wire in a manner such
that the two-plate sections are pulled bodily towards each other so
that these plate sections move from their normal positions (FIG. 5)
to the position shown in FIG. 6. This movement of the plate
sections towards each other takes place because of the fact that
the wire receiving slots 12, 14 are not in alignment with each
other but are located such that there center lines extend obliquely
of each other and intersect as shown in FIG. 5. As the wire moves
downwardly into the slots, it engages the sharp corners of each
slot and tends to move the plates towards each other as shown in
FIG. 6. The plate sections thus have a tendency to return to their
normal positions after the wire has been inserted and exert a
continuing interface pressure on the wire. This flexure of the
plate sections as units towards each other thus provides one mode
of spring loading and gives rise to one source of contact
force.
Referring now to FIGS. 7 and 8, each plate section will also act to
some extent as a spring independently of the other plate section by
virtue of the presence of the kink 20 in each plate section. These
kinks, serve as semi-cylindrical plate springs which connect the
portions of 34, 36 of each plate section on the opposite sides of
its slot. As the oversized wire moves into the slot, the portion 34
of the plate-section will tend to be swung into a slight
counterclockwise arc when accompanying stressing of the kink 20 and
the tendency of the portion 34 to return to the normal conditions
gives rise to a further component of contact force for the
wire-slot interface.
It should be mentioned that FIGS. 5-8 show the deformation
phenomena in exaggerated form for purposes of illustration. In a
specific connecting device, the flexure of the plate sections
towards each other and the displacement of the plate portion 34 may
or may not ba apparent upon visual inspection but the forces which
give rise to these deformations will tend to cause the movements
illustrated in the drawing. It should also be mentioned that a
given connecting device in accordance with the invention will not
necessarily be significantly deformed in both modes illustrated and
one mode of deflection may be of more significance than the other.
The actual behavior of the connecting device will be dependent upon
such factors as the thickness and physical properties of the metal
stock, the wire size relative to the slot widths and the stiffness
of the kink 20.
It will be apparent that the advantages of the kink 20 can be
realized in the manufacture of connecting devices having a single
plate rather than a pair of plate sections in accordance with the
preferred embodiment of the instant invention. For example,
connecting devices of the type shown in U.S. Pat. No. 3,388,370 can
to advantage be provided with kinked plates for purposes of
accurate manufacture of the slot width and the achievement of the
spring effect of the kink 20. An individual plate section having a
wire receiving slot therein may be stressed, upon insertion of a
wire into the slot, in a manner such that the two parts of the
plate section would move apart but would remain co-planar; in other
words, insertion of the wire might cause partial flattening of the
kink 20 rather than pivoted movement of one part of the plate
section. In both types of connecting means (the V-shaped type of
FIG. 1 and a simple flat plate having a wire-receiving slot
therein) the kink functions as a spring which stores energy for
maintaining contact force at the electrical interface.
Aside from the benefits of improved contact force effects described
above, the invention provides other advantages. For example, the
edges of the slots formed by the intersections of the plate
surfaces in the sides of the slots tend to cut into the insulation
while the wires are being inserted and this feature results in
cleaner and more positive penetration of the insulation. These same
corners dig into the wire after it has been inserted and further
contribute to the achievement of a long lived low resistance
electrical connection. The V-shape of the connecting device is
advantageous in that it is a relatively rigid and stable structural
shape even if the counting device is formed of thin stock metal. As
will be explained below, this V-shape is well adapted to close
spacing of adjacent connecting devices on a printed circuit board
and in a multi-contact connector.
Connecting means as illustrated and explained in FIGS. 1-8 can be
used for a wide variety of specific connecting devices and for
specific purposes. FIG. 9 shows a device for connecting a tap wire
40 to a through wire 38, this connecting device comprising two
connecting means 42, 44 of the type previously described which are
integral with each other along one edge of each plate-section at
46. A connecting device as shown in FIG. 9 can be manufactured by
simply stamping the required slots in a blank and bending the blank
to form the offset individual connecting means for the tap wire and
the through wire.
FIGS. 10 and 11 show a multi-contact connector for forming
butt-splice connections between three pairs of wires extending
axially towards each other. The connector contains three separate
W-shaped connecting means mounted in a housing having a base and a
cap section. Each connecting means 48 comprises two separate
connecting means 50, 52 which are integral with each other by means
of a connecting bight 54. The housing base section 56 has
upstanding sidewalls 58 and barriers 60 extending between, and
parallel to, the sidewalls to form three separate compartments, one
for each connecting means 48. The cap section 62 has integral
depending flanges 64 with inwardly directed lower ends 66 that are
adapted to snap to grooves 68 in the sidewalls 58 of the base
section. Cap section 62 also has depending ribs 70 which are
located such that they will push the wires into the splice
connectors when the cap section is assembled to the base section.
The housing may be of any suitable insulating material such as a
firm thermo-plastic.
A connecting means in accordance with the invention can be provided
on known types of contact terminals as shown in FIGS. 12 and 13.
FIG. 12 shows an electrical contact pin 71 having an enlarged
intermediate section 76 which is connected by a neck 74 to a
connecting means 72 in accordance with the invention, the
connecting means being oriented relative to the axis of the pin
such that it is adapted to receive a conductor 78 extending
transversely of the axis of the contact pin. A terminal of this
type can be used in an electrical connector as described in FIG. 14
below. FIG. 13 shows a pin 71a having a connecting means 72a
integral therewith, this connecting means being oriented so as to
receive a wire extending coaxially with respect to the contact
pin.
FIG. 14 shows a multi-contact electrical connector in accordance
with the invention for connecting the individual conductors 82 of a
ribbon-cable 80 to the conductors 98 of a printed circuit board 94.
The cable 80 contains a plurality of parallel connectors, each of
which is surrounded by plastic insulation 84 that extends between
adjacent conductors as a web 86. The connector of FIG. 14 comprises
a block 88 of insulating material having cavities extending
therethrough in which electrical contact pins 71 are mounted. The
connecting means 72 on the upper ends of the contact pins are
arranged in a row with the spacing between adjacent connecting
means of adjacent terminals being equal to the spacing between
adjacent conductors 82 of the cable. To connect the individual
conductors 82 of the cable to the connecting means 72 of the
terminals, it is merely necessary to locate the cable above the
terminals with the conductors in alignment with the slots and
insert the individual conductors into the individual connecting
means. This inserting operation can be carried out by a tool of the
type shown in FIG. 1 or the conductors can be inserted
simultaneously by a tool having an inserter for each conductor in
the cable. A suitable cover 96 can be provided on the block 88 as
shown. The pins 71 are adapted to enter cavities 92 in a
complementary connector block 90 which cavities contain contact
sockets which are connected by soldering to the conductors 98 on
the printed circuit board 94.
FIG. 14 illustrates a further advantage of the invention in that
the individual connecting means 72 can be nested within each other
and close spacing of the contact terminals in the block 85 can be
achieved, notwithstanding the fact that the plate sections are of
substantial width.
FIG. 15 shows a printed circuit board 94 having a plurality of
connecting means 2 in accordance with the embodiment of FIG. 1
mounted thereon. The post portion of each connecting means extends
through the printed circuit board and is soldered to an electrical
conductor 98 on the underside of the board. The connecting means 2
are nested within each other so that there is a minimum of space
separating adjacent connecting means 2. This view thus illustrates
the fact that connections can be made with printed circuit board
conductors 98 that are extremely close to each other.
Changes in construction will occur to those skilled in the art and
various apparently different modifications and embodiments may be
made without departing from the scope of the invention. The matter
set forth in the foregoing description and accompanying drawings is
offered by way of illustration only.
* * * * *